Fender skirt question

We went to an open house for a new dealership in our area (Show Me Campers in Grain Valley MO - the only KC area dealership to carry TM's!)
and noticed the new TM's had a half-moon (semicircle) type fender skirt on the wheel wells. We have a 2004 model 3023 and it does not have those.

Are those just for show or can they be purchased and installed?

I've tried doing and internet search for fender skirts but all I've come up with are the molding-style ones.

Thanks!